HEATING TUBE WITH INNER GROOVES FOR LIQUID MEDIUM AND HEAT EXCHANGER USING HEATING TUBE

摘要

PURPOSE: To improve the transfer efficiency of a heating tube with inner grooves without causing the increase in pressure loss. CONSTITUTION: Annular grooves 2 that are continuously formed in a heating tube 1 at intervals in the lengthwise direction along the direction having an angle of 45 to 90° to the axis of the tube desirably have a depth (d) of 0.20 mm or above and a groove pitch P of 2 to 5 times the groove depth. Moreover, the ratio W/P of a bottom width W of the groove projection part 3 to the groove pitch P is desirably 0.1 to 0.9. Thereby, moderate turbulence is generated to the flow of liquid medium by the annular grooves, so as to improve the heat transferability between the heating tube and the liquid medium. The pressure loss is small, and the heat exchange efficiency of the entire heat exchanger is improved. By regulating the ratio of W/P, it is prevented that the groove projection part is squashed by pipe enlarging work to spoil the effects.